Abstract
To expand the capabilities of biosensors, there is a need to develop new signaling molecules. This chapter focuses on molecules, produced through genetic engineering, that combine the recognition element with a signaling element (such as a fluorophore) in an effort to optimize the signal caused by the binding of the analyte to the recognition element. These systems, while not necessarily originally developed for an optical fiber, can be immobilized at the tip of the fiber either through chemical attachment or entrapment behind a membrane. Three different systems will be examined: fluorophore-labeled binding proteins, FRET-based systems, and bacteria-based sensors. These systems use optical signaling methods to reveal the binding event, taking advantage of molecular biological techniques to optimize the signal. This chapter discusses the advantages and disadvantages of each system as well as the current state of the art of these biosensors.